[Performance evaluation of the X-ray computed tomography "TCT-700 S" (Part 1)].

Abstract

The performance of the Rotate/Rotate CT scanner "TCT-700 S" (Toshiba) was evaluated on the basis of the item entitled "User's initial acceptance tests (phase II)," set forth in "Standard of performance evaluation for X-ray computed tomography (second recommendation)" proposed by Takenaka et al. (1982). This report describes measurements for noise, contrast scale, spatial resolution, and high- and low-contrast resolution. Recommended phantoms were used to test performance. Results 1. Noise edepended on slice thickness and mAs. It increased as slice thickness decreased. No matter what the slice thickness, noise was great when mAs settings were small. Furthermore, short scan time caused considerable noise for each slice thickness. Reduction of mAs setting caused remarkable increased in noise when slice thickness were 1 mm or 2 mm Under routine examination, when thickness was 5 mm, at 120 kV, with an mAs setting of 440, scan field S(diameter 240 mm), and convolution filter FC-2, noise was 0.31%. When slice thickness was 10 mm at 120kv, 800mAs, with a scan field S (diameter 240 mm), and convolution filter FC-2, contrast scale was 1.84 x 10(-4) (cm-1/CT number). 2. When slice thickness was 5 mm, at 120 kV, with a mAs setting of 1200, scan field S(diameter 240 mm), and a convolution filter of FC-2, spatial resolution was 0.5LP/mm. 3. When slice thickness was 5 mm, at 120kV, with a mAs setting of 1200, scan field S (diameter 240 mm), and convolution filter of FC-2, minimum high-contrast resolution was 0.5 mm.(ABSTRACT TRUNCATED AT 250 WORDS)